With data from one survey only, we can’t estimate abundance without making strong assumptions about capture probability. In the case of plot surveys, we assume we know it, and with distance sampling methods (Chapter 7) we assume “capture” is certain on the line or point. Depending on the application, these assumptions may be quite reasonable; when they are not, removal or mark-recapture methods can be useful. With mark-recapture methods, animals continue to contribute information about capture probability after they have been initially captured; with removal methods, they do not. Recapture data allow us to estimate capture probability without the assumptions of plot or distance sampling methods and without removing animals from the population.
KeywordsBlack Ball Estima
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